liquid questions

[Matrioska]

Hi Guis,
I have 3 questions

1) is it possible to calcolate liquid and in a second mmnt the foam only, without re calcolate the liquid again?
2) how can I config the age/life of the liquid particles? I need they leave only 100 frames after their emission . I tryed to play with the "lifespan" without results...
3) the liquid when it is launched makes a kind of fountain, it is not linear, is it possible to achieve a linear stream without this initial splash effect?

Many thanks!

[Ivaylo Katev]

Hi,
1. yes, the foam can be calculated independently after the liquid is already simulated. to do this use the resimulation panel
2. once born the liquid can't disappear by age, you have to erase them, but i doubt that you need exactly this. better explain what you need to do (without technical terms, just the effect)
3. can you share an image?

[Matrioska]

Many thanks Ivaylo,

1) Ok, is there some tutorial how to use correct the resimulate panel?
2) I have a dishwasher with 28 emitters that works for 500 frames, I would like the older particles gradually begin to disappear to reduce the calculation and the amount of water present in the disher.
3) this is an example of fountain: http://www.barabucha.com/downloads/immagine.jpg

[Ivaylo Katev]

i see now, ok, to resolve point 3, you have to use nightly builds and flip solver.
the "mushroom" head of the stream is very typical for the grid based core, used in the old phoenix versions, it was primary fire simulator.
you have to delete the old simulator, and put a new one, created by the LiquidSim button.
for resimulation of the foam you have to export the liquid and the velocity as grid, see the "grid channels" section in the output panel.
after having the pure liquid simulation, you can add foam enabling the foam simulation and enabling resimulation in the "resimulation" panel.

[Matrioska]

thanks Ivaylo,
for the point 2, is there any solution?

[Ivaylo Katev]

just a side note to the use of "particles" in your case. the old core is grid based, there are no liquid particles. the simulation runs with almost the same speed regardless full or empty the container is. if you continue to use the official release, there will be no performance effect even if you delete the liquid. but if you need to delete liquid to prevent overload or something like that, you can use negative source.
for the flip solver the liquid amount affects the performance , but to delete old particles is not a good solution you can create negative source and put it in proper position to be not visible.

[Matrioska]

I used the negative source and it works fine.
It seams to me that the quantity of fluid increase to quickly in proportion with the jet of water.

I increased the value of quality on the conservation panel, but without aa sufficent result.

[Ivaylo Katev]

yes, the grid based simulations can produce too fast liquid grow, but the conservation does not resolve it, actually it's spf related, you have to increase the spf parameter .

[Matrioska]

The spf value is 12 and the problem remain, i try with 20.

My start frame is 0 and my stop frame is 500 but the simulation stop to 162 frame... all my test stop to 162 frames...
If I try with "load and start" not work...

[Ivaylo Katev]

are you using the official build?

[Matrioska]

demo version...
is it a limitation of demo?
My boss askeda me to evaluate phoenix before stop to use RF, our renderfarm use vray with 22 nodes so we think to change RF with PHNX.

[Ivaylo Katev]

yes, it's limitation of the demo, can't make too big sims.
well, if you are focusing on the liquids, you can't see too much using the demo. the reason is that we skipped the release this year, and the most important liquid features are not available in the last official release. in fact, phoenix was "officially" a fire simulator in version 2.2, despite the liquid tools.
my suggestion is: speak with the support, if you are a vray customer, perhaps they will agree to give you nightly build access for phoenix and some evaluation license. once you get a nightly build, you can use the dedicated liquid simulator with much better results.

[Matrioska]

can I ask you why the program doesn't use also orange particles to create the mesh?
you can see it here http://www.barabucha.com/downloads/orange.jpg

[Ivaylo Katev]

i think it's related to the iso surface level, but it's good to use the proper concepts, there are no particles here, this is the grid content, if you tweak the preview ranges you can get the grid value of the orange cells and setting the iso surface level below it, the mesh will cover them as well.

[Matrioska]

I have another big problem with my test

I can not remove that ugly effect of groove that creates the grid, also increasing a lot the resolution
You can see the image on this link
http://www.barabucha.com/downloads/stairs.jpg